1. Field of the Invention
The present invention relates generally to a distributor driving apparatus for an engine.
2. Description of the Prior Art
To obtain higher engine performance in automotive vehicles, DOHC (double overhead camshaft) engines have been widely used, in which two different camshafts for driving intake and exhaust valves separately are provided on a cylinder head. In the prior-art DOHC engines, however, since the distributor is driven by one of the camshafts by engaging a driving gear fixed to a front end of the camshaft with a driven gear fixed to the distributor, there exist various problems in that the gear arrangement positions and the distributor inclination angle are restricted and therefore the distributor projects beyond the engine rocker cover, thus increasing the engine total height.
Further, since the distributor driving gear is fixed to either one of the two camshafts, there exists another problem in that the two camshafts cannot be used in common and therefore additional machining process is required, thus decreasing the productivity of the engine. Furthermore, since the distributor is directly driven by the camshaft in gear-to-gear engagement relationship, the revolution of the distributor is subjected to the harmful influence of backlash of the gear fixed to the camshaft whose rotative speed tends to fluctuate, thus deteriorating ignition timing precision. To overcome this backlash problem, Japanese Published Unexamined (Kokai) Utility Model Application 60-58874 discloses a distributor driving gear apparatus whose teeth are alternately magnetized into N and S poles, for instance.